High speed reclosing mechanism



Sept. 8, 1942. c. THUMIM HIGH SPEED RECLOSING MECHANISM Filed June 1%.1956 l t l W 1 I T. 3 9 7 Z) M. m 6 5 I W 4 I 2 iluFfa ilfl g C aInventor", Com! Thumim, b 8. I

Patented Sept. 8, 1942 I HIGH SPEED BECLOSING MECHANISM Carl Thi'imim,Lansdowne, Pa., assignor to General Electric Company, a corporation ofNew York Application June 17, 1936, Serial No. 85,789

11 Claims.

My invention relates to high speed reclosing mechanisms for apparatusoperable between two positions, such as, for example, an electriccircuit breaker operable between closed and open circuit positions.

In electric distribution systems where continuity of service is a veryimportant factor, means have been provided for quickly reclosing anelectric circuit breaker one or more times after automatic opening onthe assumption that most faults are of a temporary nature, such assurges due to lightning for example. However, the means heretoforeemployed for effecting quick reclosure. have either been quiteexpensive, such as for example an arrangement using a pair of circuitbreakers one of which is to be closed when the other is tripped open, orhave failed to take advantage of the comparatively brief existence ofthe fault.

From the standpoint of service continuity, the ideal condition is thatthe breaker be reclosed instantly after clearing of the fault by thebreaker. A well designed breaker can clear a fault within a few inchesof breaker travel. In connection with thisoperation, however, it shouldbe borne in mind that the function of a circuit breaker is not only toopen a circuit and clear faults, but also to maintain the circuit clearunder adverse voltage conditions. That is, the length of stroke of thecircuit breaker must be suiilcient to prevent restriking of the are evenwhen the line voltage is several times that of normal. Accordingly,where standard opening and closing mechanisms are employed reclosuredoes not actually start until the full opening stroke has beencompleted.

It will, therefore, be apparent that when the design factors, such asrequired length of stroke, mass and inertia of the moving parts, etc.,of a conventional oil' circuit-breaker of high interpanying drawing, andthe features of novelty which characterize my invention will be pointedout with particularity in the claims annexed to and forming a part ofthis specification.

Referring to the drawing, the single figure thereof is a partlydiagrammatic illustration of a f high speed reclosing mechanism for anelectric circuit breaker embodying the present invention.

The high speed reclosing mechanism is shown as applied to a conventionaloil circuit breaker generally indicated at I, although it should beunderstood that the mechanism may be as readily applied to apparatusoperable between two positions wherein quick return or reclosing to oneof said positions is desired. The actuating means comprises in thepresent instance a pair of centrifugal devices of the well known flyballtype, generallyindicated at 2 and I, the devices being operativelyinterconnected by a floating lever 4 which is in turn connected at avertically guided point 5 intermediate said devices to the operating rod8 of the circuit breaker.

The circuit breaker as shown is in the closed.

circuit position, the fixed contact and are extinguishing structures Iand I being bridged by the movable contact structure 9. The lift rod Illfor operating the bridging contact '9 is connected through suitablelinkage structure to the operating rod t. The linkage structure is ofthe straight-line type, a link il having a fixed pivot at I! and a leverI! having a fixed pivot at It being interconnected by a link It so as toimpart to the lift rod at ll substantially straight-line motion. Thelever i3 is interconnected through a pair of bellcranks II, II and alink I! to the operating rod 0. Accordingly, when the rod I is free tomove upwards, the bridging contact 8, under the influence of spring 20,moves downwards to the open circuit position. Conversely, downruptingcapacity are taken into account, the problem of rapidly reclosing thecircuit breaker terminates the opening operation and the reclosingoperation is initiated at that point.

My invention will be more fully set mm in the following descriptionreferring to the accomward movement of the operating rod 6 causesclosing of the bridging member against the bias of spring 20.

Each of the centrifugal devices 2, 2 comprises ver 4 is connected to themember 20.

The operation of the centrifugal device is believed to be apparent fromthe above description, energization of the motor 2| of device 3, forexample, to spin the fiyballs causing extension of the fiyball linkageso as to cause counter-clockwise rotation of the resetting weight 28,and counter-clockwise rotation of the bellcrank 3| through thethrust-transmitting toggle 23-40. In device 2, extension of the flyballscauses clockwise rotation of weight 23 and crank 3|.

A tripping solenoid 33 is associated with the toggle 29-3U so as tocause movement of the toggle knee 34 beyond the line of centers forbuckling the toggle. Accordingly, the mechanism is trip-free inoperationsince buckling of the toggle at any point during the operationof the centrifugal device permits reverse movement of the bellcrank 3|.

Assuming now that the circuit breaker is in the open circuit positionand that both centrifugal devices are cleenergized and reset similar todevice 2, the floating lever 4 would then be in a horizontal positionadjacent the fixed spring buffers 35 and 35. The bufiers.35 and 36 areadapted to be engaged, respectively, by the bellcranks 31 for bothcushioning the shock of an opening operation and for providing a pivotfor the lever 4. In this initial position, auxiliary switch 48 would beclosed under bias of its spring 48' and switch 48 would be held open bylatch 49o.

If th circuit breaker is simply to be used for normal opening andclosing operation, that is, reclosing under the direction of anoperative after an opening operation, the manually controlled switch at31 is closed on contact 31a, thereby energizing the motor contactor coil38 from the control source 39.

This control circuit also includes auxiliary switches 40 and 41. Sincethe centrifugal device 3 in the open circuit position of the breaker isin the same position a device 2, the auxiliary switch M will be closedunder the bias of spring 4!. Also, the auxiliary switch 40 which isnormally biased closed by its spring 40 will be closed.

When the motor contactor contacts close at 38', the motor 2i will beenergized from th control source and th floating lever 4 will be rotatedclockwise through the flyball linkage and thrust-transmitting structureor device 3 above described. During operation of the linkage a cam 46carried thereby causes opening of the auxiliary cutoii switch 4! therebyopening the motor contactor 3B and deenergizing the motor.

The circuit breaker is now closed and the mechanism remains in theposition shown until the breaker is tripped. The tripping may baccomplished in a conventional manner by a current transformer at 42associated with th main power circuit controlled by the breaker l, and arelay 43 for completing the circuit of the trip coil 33. An auxiliaryswitch 44, normally closed by the lever 4 when th breaker is closed,prevents operation of the trip coil 33 when the breaker is open. Formanual tripping a push button switch 45 is connected across the relay43.

Assuming now that a fault occurs on the line, the relay 43 will beactuated to energize the trip coil 33 from source 39 to cause collapseof the toggle 29-30. This results in counter-clockwise rotation of lever4.to the original horizontal position due to the bias of breaker spring20 and opening of the breaker. Th operative may then, if he desires,reclose the breaker by closing switch 31 on contact 31a, therebyrestarting the above described cycle.

Where automatic reclosing is desired, an auxiliary or cutoiI switch inthe motor control circuit of the reclosing device 2 is closed, thisswitch being opened and latched in open position in accordance with thereclosing operation for the purpose oi preventing pumping" or reclosingindefinitely.

To this end, after the breaker has been closed by centrifugal device 3,the operative's switch 31 is thrown from contact 31a to contact 3'").This energizes the latch coil 49b for releasing latch 49a and permittingclosing of cutoif switch 49 by its biasing spring 49. If now the breakeris tripped open, the auxiliary switch 43, which is held open in thclosed position of the breaker by the lever 4, is closed by its biasingspring 43'.

The motor contactor coil 41 for the device 2 is thereby energized fromthe control source 39.

Energization oi the motor circuit through the contactor contacts 41causes extension of the fiyball linkage or device 2 andcounter-clockwise rotation of the lever 4 with respect to the buffer 35for closing the circuit breaker. The devices 2 and 3 will now be inpositions opposite to those shown in the drawing. In moving to theclosed position, device 2 through the cam member 50, which is moveddownwards by the fiyball movement, causes opening or the auxiliary orcutoli switch 49 to deenergize the contactor coil and open the motorcircuit. The cutoff switch 43 is then held open by latch 49a. Also,lever 4 in moving counter-clockwise causes closing of the auxiliarycontacts at 5|.

In this position actuation of the tripping relay 43 causes energizationof the tripping solenoid 53, thereby causing buckling of the toggl 2930,clockwise rotation of the lever 4 and opening of the breaker by thebreaker spring 20.

Accordingly, when the operatives switch 31 is held closed on contact 31auntil the breaker is closed and then is closed on contact 311) torelease and close the auxiliary switch 43, an automatic reclosing cycleis prepared so that in response to a line disturbance the breaker istripped open, reclosed, and if the fault persists is again tripped open(being trip-free). The mechanism remains in thi position until theoperative performs another control operation, namely manual closing ofswitch 31 on contact 31a and then on contact 31b, to prepare for anotherautomatic reclosing cycle.

In addition to providing an electric interlock between the motors of thedevices 2 and 3, the auxiliary or reclosing switches 40 and 48 serve tocause initiation of the operation of the centrifugal device forreclosing the breaker during and prior to completion of the circuitopening movement. That is, assumin that the operatives switch 31 isclosed on contact 31b for automatic operation and the circuit breakerhas been previously closed as above described, the tripping operationwill cause rotation of lever 4 towards the buffer 35. Since the lever 4in the position shown hold the switch 48 open, immediately upon trippingthe switch 48 will close causing energization of the motor contactorcoil 41 and actuation of the device 2. This operation is so rapid thatthe device 2 starts lowering its end of the lever 4 before the oppositeend of the lever reaches the buiier 35. In other words, there is anintermediate point in the operation where the circuit breaker operatingrod 6 is retarded in its opening movement. By reason of the floatingsponsor relation of the lever l to the operating mec nisms and-breakerrod C, the right end (as viewed) of the lever is moving down at the sametime the left end is moving up resulting in a rapid but gradual andsmoothgetardation of and change indirection of motion of the breaker rod8, There is therefore no shock or impact as would be the case were thereclosing force directly to oppose the moving mass to eifect reclosure.

This retardation or dashpot eii'ect, which is applied beiore completionof the breaker opening stroke, is particularly advantageous since theinertia oi the moving parts is rapidly overcome and the device 2 isthereby more eiiective rapidly to reverse the operation of the rod 8 andreclose the breaker. It will, therefore, be seen that the reclosingoperation is actually in progress before completion of the openingoperation.

It should be understood that my invention is of said circuit breaker andto reclose said circuit breaker within a reclosin tim cycle that ismaterially less than a full stroke opening and reclosing cycle.

5. A high speed reclosing mechanism for an electric circuit breakercomprising a pair of separate operating means, a floatinglevenoperatively interconnecting said operating means, said not limitedto specific details of construction and arrangement thereof hereinillustrated, and that changes and modifications may occur to one skilledin the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A high speed circuit breaker reclosing system comprising a circuitbreaker having relatively movable contact structure, means for actuatingsaid contact structure toward closed circuit position, means actuatedindependently of the operation of said actuating means for tripping andcausing opening movement of said contact structure, and means operatedsubsequent to said tripping means and prior to completion of the openingstroke of said contact structure to initiate the operation of saidactuating means to reclose said contact structure within a fraction orthe time required for a full stroke opening and reclosing cycle.,

2. A high speed reclosing mechanism for an electric circuit breakercomprising two separate operating means, means controlling one of saidoperating means for closing saidv circuit breaker, means for causing acircuit opening operation of said circuit breaker, and means responsiveto said opening operation for controlling the other of said operatingmeans so as to cause initiation' of a reclosing operation of saidcircuit breaker prior to completion of said circuit opening operation.

3. A high speed reclosing mechanism for an electric circuit breakercomprising a pair oi. separately actuated operating means, meansinterconnecting said operating means and said circuit breaker, tripping,means selectively associated with each of said operating means forcausing opening of said circuit breaker, and means responsive to atripping operation at one of said operating means for initiating theoperation 01' the other operating means to reclose said circuit breakerprior to completion of the circuit opening movement.

4. A high speed circuit breaker reclosing system comprising a circuitbreaker having relatively movable contact structure, means for biasingsaid contact structure through a full stroke to v open circuit position,means for actuating said contact structure toward closed circuitposition, and means actuated by and in accordance'with movement of saidcontact structure through a fractional part of' said opening stroke forinstantly initiating the operation of said actuating lever beingconnected at an intermediate point to said circuit breaker, latching andtripping ,means selectively associated with each .0! said operatingmeans for holding and causing release respectively of the correspondingend of saidlever and circuit opening movement of said breaker, andcontrol means responsive to a tripping operation at one end of saidlever for initiating the operation of the operating means at the-otherend or said lever prior to completion of the circuit opening movementfor reclosing said circuit breaker.

6. An automatic reclosin mechanism for apparatus operative between openand closed positions comprising actuating means for closing saidapparatus, a relay for controlling said actuating means prematurely tocheck the opening stroke means, tripping means for causing opening ofsaid apparatus, and control means actuated in accordance with saidopening operation for positively causing initiation of the operation ofsaid relay for controlling said actuating means prior to completion ofsaid opening operation wherebysaid actuating means effects retardationof the final opening movement during said initial operation.

7. A high speed reclosing mechanism for an electric circuit breakercomprising two separately operated motive means, structure common tosaid motive means for operatively connecting the same to said circuitbreaker, said structure arranged so that said circuit breaker can beclosed a; selective operation of said motive means, tripping meansselectively associated with each of said motive means for causingopening of said circuit breaker, and control means responsive tooperation of one of said tripping meansfor causing initiation of theoperation of the motive means associated with the other of said trippingmeans to reclose said circuit breaker, said lastnamed motive means beingrelated to said structure so as to cause retarding or the circuitbreaker final opening movement during said initial op- I eration.

8. A high speed reclosing mechanism for an electric circuit breakercomprising a pair of separately actuated centrifugal operating devices,a floating lever interconnecting said devices, said circuit breakerbeing operatively connected todevice causing opening of said circuitbreaker, and a control switch arranged to close in accordance with saidopening movement for energizing the other of said centrifugal devicesthereby initiating counter-rotation of said floating lever and reclosingof said circuit breaker.

v 9. A high speed circuit breaker reclosing system comprising a circuitbreaker having relatively movable contact structure, an actuating devicefor moving said contact structure to cloud circuit position, a secondactuating device includtripping means for causing movenien" r co: actstructure toward open circuit 130 actuating device for effectingreciosing movement of said contact structure, and means actuated by andin accordance with movement oi said contact structure toward opencircuit position for initiatin the operation of said third actuatingdevice to reclose said circuit breaker prior to completion of the fullcircuit opening stroke of said contact structure.

10. A high speed reclosing mechanism for a circuit interruptercomprising an operating member movable to open and to closed position,means for actuating said operating member toward closed position, meansactuated independently of the operation of said actuating means 'fortripping and causing opening movement of said operating member, andmeans operated subsequent to said tripping means and prior to completionof the opening stroke of said operating to initiate the operation ofsaid actuating means to reclose said operating member within. a fractionof the time required for a full stroke opening and reclosing cycle.

11. A high speed circuit breaker reclosing system comprising a circuitbreaker having relatively movable contact structure, tripping means forcausing opening of said contact structure, means for causing high speedreclosure of said contact structure in response to the opening operationthereof, trip-free means associated with said reclosing means, a circuitcontrolling means responsive to the openin of said contact structure forrendering inoperative said tripping means, and a second circuitcontrolling means also responsive to the operation of said contactstructure for transferring the tripping control to aid trip-free meansduring reclosure of said circult breaker.

CARL 'I'HUMIM.

